Fuel injection system



No v. 19, 1957 J. M. WHITE ETAL FUEL INJECTION SYSTEM 4 Sheets-Sheet 1Filed July 2, 1956 E .E V f mWR m m mR AF 0 .JL 4 A m h/ 9 a G J 0 w x Fk I j b H 7 6 ATTORNEY Nov. 19, 1957 .J. M. WHITE ETAL FUEL INJECTIONSYSTEM 4' Sheets-Sheet 2 Filed July 2, 1956 umnn ugm FIG.3.'

. E Y ET E mTR m MM 0 w n N II c .A M WR AF L A fi B Nov. 19, 1957 J. M.WHITE ETAL FUEL INJECTION SYSTEM 4 Sheets-Sheet 3 Filed July 2, 195aFIG.5.

v INVENTOR. 2

JACK M. WHITE BY ALFRED C. KORTE AT TOBNEY Nov. 19,, 1957 J. M. WHITEETAL FUEL INJECTION SYSTEM 4 Sheets-Sheet 4 Filed July 2, 1956 FIG.7.

INVENTOR. JACK M. WHITE ALFRED C. KORTE AT TORNEY United States PatentTie 2,813,522 Patented Nov. 19, 1957 FUEL INJECTION SYSTEM Jack M.White, Normandy, and Alfred C. Korte, St. Louis, Mo., assignors to ACFIndustries, Incorporated, St. Louis, M0,, a corporation of New JerseyApplication July 2, 1956, Serial No. 595,410

24 Claims. (Cl. 123-119) This invention relates to a system for feedingfuel under pressure to an internal combustion engine and, morespecifically, to a system of this type wherein the fuel flow to theengine is metered by varying either the fuel pressure differentialacross one or more fuel flow metering restrictions or the area of theserestrictions in proportion to or in accordance with the rate of air flowto the engine, which can, in turn, be measured directly or regarded as aparameter determined by one or more of the engine vari ablesdensity,engine speed, and throttle opening.

According to this invention, the engine is supplied with air through asuitable air induction system, the entrance of which is controlled by amanually operated throttle valve. lf the engine has a plurality ofcylinders, which is usually the case, a manifold with a plurality ofoutlets connects with the inlet ports of the several cylinders. The fuelis supplied from a substantially constant pressure source, which may bea closed reservoir, and flows through a fuel passage to one or morenozzles opening into the air induction passage adjacent the engine inletport or ports. Between this source and the nozzle inlet is a fuel flowmetering restriction.

A source of air under constant pressure connects with the fuel source tourge the fuel to flow through the fuel passages and the flow meteringrestriction. Another connection from the air pressure source to the fuelpassage downstream of the metering restriction and upstream of thenozzle outlet tends to retard the flow of fuel through the flow meteringrestriction. The air pressure in this connection is controlled to varyin accordance with variations in air density posterior of the throttlevalve or by engine speed and the degree of throttle opening.

It will be readily apparent that in such a system any differentialbetween the fuel pressure at the fuel source and the air pressuredownstream of the fuel flow metering restriction will cause the fuel toflow at a rate proportional to the square root of the pressuredifferential across the fuel flow metering restriction or orifice. Whenthis pressure differential is suitably controlled, fuel flow can bemaintained substantially proportional to air flow through the engineinduction system.

A separate hydraulic circuit having a variable output pressure acting onan air pressure regulator controls the airpressure differential appliedto the fuel by variably controlling the air pressure supplied downstreamof the fuel flow metering restriction.

The hydraulic circuit includes a constant displacement pump driven atengine speed, a direct pressure connection between this pump and the airpressure regulator, and a bypass hydraulic circuit around the pump,including a variable area orifice suitably operated by either throttleopening and/ or manifold pressure posterior of the throttle valve. Forany given setting of the orifice in this hydraulic circuit, the outputpressure imposed on the air pressure regulator will vary as a squarefunction of engine speed.

The action of the air pressure regulatorzresponds to this outputpressure from the hydraulic circuit to produce changes in air pressurewhich are inversely proportional to the pressure changes in thehydraulic circuit.

As an alternative to the above-described arrangement for regulating theair pressure differential, a modification contemplates a structure inwhich a separate hydraulic circuit connects with the air pressureregulator by way of metering restriction. The hydraulic pressure in theregulator is varied according to variations in air flow to the engine bya controlled outlet downstream of the metering restrictibn in adischarge line leading to the intake of the pump. The controlled outletmay be a variable orifice such as a tapered needle in a restrictionoperated linearly by movements proportional to the air flow to theengine to obtain pressure changes in the hydraulic circuit proportionalto air flow to the engine.

The advantages and novel results obtained with this system will becomemore apparent from the accompanying detailed description taken with theaccompanying draw ings, in which:

Fig. 1 is a schematic representation illustrating the fuel and aircircuits with their controls.

Fig. 2 is a schematic representation of a modification of the inventionillustrating the fuel and air circuits and their controls.

Fig. 3 is a schematic representation of a second modification of theinvention illustrating the fuel and air circuits and their controls.

Fig. 4 is a detailed view illustrating one :form of fuel nozzle which isused in the third modification.

Fig. 5 is a schematic representation of a third modification of thesystem shown in Fig. 1.

Fig. 6 is a cross-sectional view of the nozzle used in Fig. 5.

Fig. 7 is a schematic representation of a fourth modification of thesystem shown in Fig. 1.

The system about to be described is adapted to be applied to the airinduction system of a conventional piston engine. It is well understoodin the art that such systems include a single or dual manifoldarrangement with one or more throttle controlled intake stacks leadingto a manifold with plural outlets connected to the intake ports in theengine. Since the intake system or manifold forms no part of the presentinvention, the specific features thereof are not shown or described indetail.

In Fig. 1 such an induction system has been shown diagrammatically ascomprising an air intake stack 1 which is connected with and forms aportion of an intake manifold 2 having a plurality of outlets 3 and 4for connection with the several intake ports in the engine. It is alsoassumed that the engine has a suitable ignition system controlled by asuitable ignition switch of the key type, for example, as illustrated at6. In addition to controlling the ignition of the engine, the key switch6 also controls a circuit from the battery B through a solenoid operatedvalve 7, which is spring closed. The purpose of the valve is to cut offthe fuel to the engine when the ignition switch 6 is turned off. Themanner in which itoperates to perform this function will appear moreclearly asthis description proceeds.

In the system schematically illustrated in Fig. l, a pulley 9 on a shaft10 is arranged to be suitably driven at engine speed by means of a beltbetween the pulley 9 and a suitable pulley on the engine (not shown).The shaft 10, in turn, powers a plurality of pumps 11, 12 and 13, all ofwhich are connected to be driven from the line shaft 10.

The pump 11 supplies fuel to the engine as regulated by a fuel systemhereinafter described, of which it forms a part. Fuel may be supplied tothis system from a suit able source, such as a tank, connecting withline 15. The outlet 16 from the pump has a by-pass 17 containing apressure responsive relief valve 19 operated by a spring 20, so that theexcess delivery from the pump 11 may be by-passed from the outlet to theinlet, and thereby limit the pressure in the supply line 16 extending tothe reservoir 22. For example, if the pressure in the supply line 16 1s30 pounds or less gauge, the outlet from the supply line 16 may beeasily controlled by a float valve 23 of conventional design operated bya float 24 in a fuel reservoir 22. charged with air at about 25 poundsgauge.

A line 25 extends from the outlet of the fuel bowl 22 to and through thesolenoid operated valve 7 to a plurality of branches 26, 27, etc.,connecting with fuel nozzles 36, 37, etc., usually arranged to supplyfuel adjacent each manifold outlet 3 and 4. Each branch 26, 27, etc.,has a restricted metering outlet 46, 47, etc., in the connection to thefuel nozzles 36, 37, etc.

The fuel restrictions 4-6, 47, etc., above described cornprise the mainfuel metering restrictions in the fuel system. and, in order to controlthe amount of fuel delivered through these fuel restrictions or meteringorifices, it is necessary to control the pressure drop across each. The

system for directly performing this function is pneumatic and comprisesan air blower 12 driven from the shaft having an air inlet 50, whichmay, if desired, be connected with the inlet stack 1 above the throttle.An air discharge line 51 connected with the outlet from the blower 12has a by-pass line 52 controlled by a suitable spring-pressed reliefvalve 53. The setting of this valve is such that the discharge airpressure is maintained at approximately pounds pressure gauge. Thispressure is supplied to a regulating device (generally designated R) bythe line 51, and through line 54 to fuel reservoir 22. i

The regulator R has a diaphragm operated inlet valve. 55 operated to andfrom a seat by air pressure acting downstream of the valve 55 on adiaphragm 57 backed by a compression spring 58 acting in a direction toopen the valve 55 and increase the pressure acting on the diaphragm 57.A stem 59 integral with the valve 55 is connected by a reverse linkage60 with a stem 51 secured to a diaphragm 62 exposed to fluid pressure inthe line 63. The line 63 is supplied with fluid under pressure from anhydraulic circuit which is regulated by an engine speed responsive andthrottle position responsive mechanism to be later described herein, andthis pressure acting on the diaphragm 62 is opposed by the force of aspring 64 acting in a balancing direction. The springs 58 and 62determine the minimum air pressure supplied by regulator R. Diaphragmchamber 56 is connected bv a line 65 having a plurality of branches 66,67, etc., in turn connected to the fuel nozzles 36, 37, etc.

The outlet from each of these nozzles is a metered restriction such as76, 77, etc., which is so selected as to size that when the pressuredrop across each restriction i as much as 15 pounds, the flow throughthe nozzle will always be at critical speed, and variation in manifoldpressure will therefore have no effect upon the pressure inside thenozzle, and consequently no effect upon fuel metering.

In order to vary the pressure in the air line 65, and thus the pressuresupplied to each fuel nozzle, 21 regulating pressure is generated andsupplied to the line 63, which regulating pressure varies according toany change in throttle position or engine speed. This circuit includes afluid pump 13 driven from line shaft 10 and connected to the reservoirby means of a supply line $1. A fluid discharge line 82 connects withthe pump 13 and with a variable metering restriction device 83 which hasa return line 92 to the reservoir 80. This variable rneterint devicecontains an orifice controlled by a tapered needle 84 biased to an openposition by a spring 85 acting beneath the head 86. The motor vehicle orengine of the motor vehicle mounts the usual accelerator pedal 87connected by rod 88 with a pivoted cam 89. Within the air intake to themanifold is a throttle valve positioned by a lever arm connected by arod 91 with the same cam 4 89. The face of the cam 89 rides on the headof the metering stem or rod 84, varying its open position with throttlemovement. The pressure generated by the pump 13 is communicated to theregulator R by the line 63, as has been described.

Operation When the engine is not in operation, the ignition key 6 isturned to the off position, and the spring-pressed solenoid operatedvalve 7 is closed, thereby sealing off the line 25 so as to maintain thefuel supply part of the system under charging pressure. This means thatthe fuel source 22 remains pressurized at 25 pounds, which is thelimited output pressure from the blower 12. A suit able check valve maybe provided anywhere in the line 54 for this purpose. Any fuel beyondthe valve 7 may leak into the nozzles 36, 37, etc., where it will betrapped. This trapped fuel in the fuel nozzles forms a reservoir of fuelwhich is useful on engine starting, and eliminates the necessity of anoversizcd fuel pump for this purpose.

To start the engine, the ignition switch 6 is turned to the on position,energizing the solenoid valve 7 and opening communication through theline 25 from the source of fuel 22 under pressure to the fuel nozzles36, 37, etc. The engine is then cranked, which rotates the pulley 9 anddrives each of the pumps 11, 12 and 13. At cranking speed, the pressuredelivered by the pump 13 against the diaphragm 62 will be at a minimum,so that valve 55 will be opened by spring pressure, allowing air underpressure to leave the blower 12 and reach the nozzles 36, 37, etc., byway of the connecting line 65. This air pressure is suflicient todischarge fuel through the metering orifices 76, 77, etc., in thedirection of the intake ports of the engine connected with the outlets 3and 4 of the manifold. Since some fuel will be trapped within thenozzles, and since the pressure on the fuel bowl is high, this mixturewill be on the rich side, suitable for starting purposes. If the fuellevel within the float bowl. 22 drops during the cranking operation orafter the engine starts to run, float 24 will open valve 23, permittingfuel to enter from the pump 11 by way of the line 16. When normal fuellevel is reached in the bowl 22, float valve 23 is closed so as to holdthe proper fuel level. The proper level for the fuel is adjacent to butnot above the outlets 76, 77, etc., of the fuel nozzles in the manifold.

After the engine begins to run under its own power, full air pressurewill be delivered by the blower 12, and the pump 13 will reach fulloutput. Thereafter, the output from the blower 12 will be limited toapproximately 25 pounds by the by-pass control 53, while the output ofpump 13 will vary directly as engine speed, since it is a constantdisplacement pump driven at engine speed through the pulley 9.

The needle 84, at closed throttle, is in a position to form a minimumrestriction to flow from pump 13 to reservoir 80. The regulatingpressure in line 63 will be relatively low under these conditions withthe engine idling. This pressure imposed on diaphragm 62 is notsuflicient to overcome spring force alone, and the regulator will moveto a position opening valve 55 until fluid pressure on diaphragm 62 andair pressure on diaphragm 57 balance spring forces. When regulator R isproperly adjusted, valve 55 will have little throttling effect at engineidling speed-only sufficient to produce a pressure drop of a few inchesof water from full blower pressure of 25 pounds gauge. Full blowerpressure is always imposed upon the fuel within the float bowl 22.Consequently, with only a few inches of water pressure drop availablebetween the air pressure upstream and downstream of the fuel meteringorifices 46, 47, etc., to cause fuel flow, the rate of fuel flow will berelatively low. To obtain the proper rate of fuel flow demanded by theengine at idling speed, either the needle 84 or the spring pressure inthe regulator R can be adjusted.

When the throttle 90 is opened by the accelerator pedal, tapered needle84 moves into the orifice, causing an immediate pressure rise in theregulating system. This gain in pressure acting on diaphragm 62unbalances the regulator, moving the valve 55 toward closed positionuntil spring force again balances the fluid pressures on diaphragms 62and 57. Valve movement will be limited by decreasing air pressure on thediaphragm 57 as a result of the increased throttling by valve 55. As theair pressure is decreased by valve 55, the pressure differential acrossthe metering restrictions 46, 47, etc., increases because the airpressure drops downstream of each metering restriction to cause anincrease in fuel flow from each nozzle to enrich the mixture of fuel toair for acceleration.

As engine speed increases, the demand for fuel will increase, requiringincreasing rates of fuel flow past the fuel metering restrictions toeach nozzle. Since the pump 13 is a constant capacity pump driven atengine speed, then delivery from the pump increases linearly with enginespeed. 'Flow past the needle 84 does not increase linearly, however, butat a rate increasing as the square root of the increase in pressure fromthe pump. This causes a pressure rise in line 63 proportional to thesquare of engine speed, and the action of the regulator R in response tothis rate of pressure rise will increase the throttling effect of valve55 to produce a pressure drop in line 65 which is inversely proportionalto the rate of pressure rise in line 63, so that the flow of fuelthrough metering restrictions 46, 47, etc., will increase linearly withengine speed.

Closing the throttle 91) from any open position causes a decrease inregulating pressure from pump 13, and thereby a sudden increase in airpressure, as springs 58 and 64 expand, opening valve 55. A decrease infuel flow occurs as the pressure differential across the orificedecreases, causing the rate of fuel flow to decrease. Since the mixtureratio of fuel to air varies directly with the rate of fuel flow, themixture becomes temporarily lean when the throttle is closed at enginespeeds above idle. This effect increases with engine speed so that, whenthe throttle is closed, fuel is substantially cut off.

The use of air pressure to regulate the pressure drop across each fuelmetering orifice provides for equal division of the flow to the severalnozzles. The air pressure regulation of fuel flow means an equalpressure differential at each metering restriction.

Instead of controlling the regulating pressure to the regulator R bythrottle position, it is possible by a simple change to control theposition of the needle 84 by manifold pressure. Such a modification ofthe invention is disclosed in Fig. 2. The same reference characters havebeen used to indicate the same parts.

The regulating pressure line 82 from the pump 13 connects with themetering device 83 and with the return line 92 to the reservoir 30. Theregulating pressure line 63 connects the metering device 83 with theregu lator R in the same manner as disclosed in Fig. 1.

In this modification, the cam $9 has a cam face cooperating with theheaded end on the metering pin 84, which is biased against the cam by aspring d5, all in the manner described above. The position of the cam,however, is controlled by a suction motor 94 connected through line 9%with the intake stack 1 of the manifold posterior of the throttle 9%.Within the suction motor is a diaphragm 96 urged to the right by aspring 97. An operating rod 98 forms a mechanical connection between thecam 39 and the diaphragm 96.

Operation According to this modification, when the engine is beingcranked, there is very little suction in the intake manifold. Diaphragm96 is not eifective, and the spring 97 rotates the cam 89 to a positionto hold the metering pin 8 3 in flow-restricting position to producesubstantially its full throttling effect on fluid circulation by pump13. Even though, during cranking, pump speed is low,

nevertheless, the regulating pressure will increase in the line 63. Asthe regulating pressure increases, spring force in regulator R will beovercome, causing valve 55 to move toward a flow restricting position.Regardless of blower speed, the pressure differential across the fuelmetering orifices 46, 47, etc., will remain high, causing a substantialfuel flow as soon as ignition key 6 is turned on and the engine cranked.Under these conditions, the starting mixture will be suitably rich.Some: of this fuel will accumulate within the nozzles 36, 37, etc., soas to be always available for enrichment on acceleration, but most of itwill be ejected by air pressure in an atomized condition. It is one ofthe features of this system that, after the engine begins to run underits own power, the air pressure available to atomize the fuel will be atleast 15 pounds, even at full throttle. The outlets of the separatenozzles are each chosen as to size to produce an air fiow at criticalspeed on less than a fifteen pound drop or differential, which meansthat the air flow ca pacity of the nozzles will be limited to a constantamount unaffected by changes in manifold pressures.

After the engine starts, the air pressure from the blower 12 willincrease to normal, say 25 pounds, so as to decrease the pressure dropacross the fuel metering restrictions 46, 47, etc. Then the regulator Rfunctions to adjust this pressure drop precisely, so that at closedthrottle it will amount to only a few inches of Water pressure. The flowof fuel depends upon the air pressure differential, which, in turn,depends upon the action of valve 55. Regulator R is, in turn, responsiveto fluid pressure in line 63, which is a function of engine speed anddensity, as hereinafter described.

Manifold suction during engine operation opens needle valve 84, loweringthe pressure in line 63 and on diaphragm 62, tending to close valve 55.The springs 58 and 64 tend to open valve 55 and, because spring forcesare the greater, the valve will open or remain open. The degree ofopening depends upon the degree of force exerted on the diaphragms $7and 62 by fluid pressures. At idle, the springs are so calibrated as toproduce a few inches of water pressure drop across valve 55. Thus theair pressure to the nozzles is only slightly under 25 pounds gauge. Thisdifferential causes a low rate of fuel flow through the meteringrestrictions 46, 47, etc., which corresponds to the fuel requirements ofthe engine at dead idle engine speed.

Any time the throttle 9t? is opened, however, there will be a change indensity (manifold pressure), which change will be reflected by acorresponding change in the position of needle 84, increasing thethrottling effect of the metering device 83. The resulting increaseinthe regulating pressure in line 63 unbalances the forces in regulatorR, moving valve 55 toward a closed position until equilibrium is reachedbetween spring force and dia phragm force. Any degree of movement of thevalve 55 in a closing direction increases its throttling effect toincrease the pressure drop and the pressure differential across the fuelmetering orifices 46, 47, etc., to increase the rate of fuel flow.Accordingly, any degree of density change operates directly on fuel flowrate. Opening the throttle effects an enrichment of the mixture and,conversely, closing the throttle acts to lean out the mixture. Thislatter effect can shut off the fuel entirely if engine speeds are muchabove idle speed when the throttle is closed.

As the engine speed increases, the engine demand for fuel will increasein a near linear relation. The delivery of the pump 13 will alsoincrease in a near linear relation with increases in engine speed. Theflow through the metering device 83 increases as the square root of thepressure output of pump 13, and therefore the pressure in line 63increases as the square of engine speed. The

response of the regulator R produces a pressure drop across valve 55inversely proportional to the pressure rise in line 63, so that airpressure downstream of the fuel metering orifices 46, 47, etc., willcause 'a pressure differential to act on the fuel, which varies directlyas the square function of engine speed. Translated into terms of rate offuel flow through fuel metering restrictions 46, 47, etc., a pressuredifferential which varies as the square of engine speed causes a varyingrate of fuel fiow bearing a near linear relation to variations in enginespeed.

When the throttle 9G is closed, manifold pressure decreases, movingneedle 84 to decrease the throttling effect of metering device 56. Asudden decrease in regulating pressure follows, and regulator Rresponds, moving valve 55 toward open until a new equilibrium is reachedbetween spring force and fluid force. As valve 55 opens, the airpressure differential decreases because the pressure acting downstreamof each fuel metering restriction 46, 17, etc., increases.

Translated into terms of rate of fuel flow, a decrease in air pressuredifferential means a lower rate of fuel flow. With the speed densitysystem described, the rate of fuel flow varies directly with manifoldpressure, and, since the latter is an indication of the rate of air flowthrough the manifold to the engine, it follows that the rate of fuelflow varies directly with the rate of air flow to the engine.

In the modification shown in Figs. 3 and 4, a system similar to thosepreviously described is illustrated in which the principal differenceresides in a novel form of fuel nozzle. According to this modification,the pressure drop across each of the fuel orifices in the respectivenozzles increases the size or area of the nozzle discharge orifice.

As in the previous views, the system is schematically illustrated, and.the engine is not shown, since it forms no part of the invention. An airinduction system suitable for use on an engine having a plurality ofinlet ports is schematically illustrated. The elements in Figs. 3 and 4which correspond with those previously described in Figs. 1 and 2, willbe indicated by the same reference characters preceded by 100.

Fig. 3 shows an engine induction system comprising an air intake stack1111 which is connected with and forms a portion of an intake manifold102 having a plurality of outlets 1113 and 1114 for connection with theseveral intake ports of the engine. The engine has a suitable ignitionsystem (not illustrated) controlled by a suitable ignition switch 166 ofthe key type. In addition to controlling the ignition of the engine, thekey switch 106 also controls a circuit from the battery B through asolenoid operated valve 1117 which is spring closed.

In Fig. 3 a pulley 1119 on a shaft 110 is arranged with respect to theengine to be suitably driven at engine speed by means of a belt betweenthe pulley 1119 and a suitable pulley on the engine (not shown). Shaft1119, in turn, powers a plurality of pumps 111, 112, and 113, all ofwhich are connected to be driven directly at engine speed by the pulley1119. The pump 111 supplies fuel to the engine as regulated by a fuelsystem hereinafter described, of which it forms a part. Fuel may besupplied to this system from a suitable source such as a tank connectingwith the line 115. The outlet 116 from the pump has a by-pass 117containing a pressure responsive relief valve 119 operated by a spring120, so that the excess delivery from the pump 111 may be by-passed fromthe outlet to the pump inlet. and thereby limit the pressure in thesupply line 116 extending to the reservoir 122. Preferably, the pressurein the supply line 116 is maintained at, say 30 pounds or less, so thatthe outlet from the supply 116 may be easily controlled by a float valve123 operated by a float 124 in the reservoir 122 which is under an airpressure of 25 pounds all the time.

A fuel line 125 extends from the outlet of the fuel bowl 122 to andthrough the solenoid operated valve 107 to a plurality of branches 126,127, etc., connected with fuel nozzles 136, 137, etc., arranged tosupply fuel adjacent each manifold outlet 103 and 104. Each branch 126,127, has a restricted metering outlet 146, as shown in Fig. 4.

The fuel restrictions 146 are at the fuel inlet for each of the nozzles136, 137, etc., and each forms a part of the main fuel metering in thefuel system. In order to control the amount of fuel delivered througheach of these fuel restrictions or metering orifices, it is necessary,of course, to control the pressure drop across each. This systemincludes a pneumatic circuit for this purpose which will be variableaccording to the engine requirements, and uniform in its effect in eachnozzle. The pneumatic circuit performing this function comprises an airblower 112 driven from the shaft having an air inlet 150 which may, ifdesired, be connected with the inlet stack 101 above the throttle. Anair discharge line 151 connected with the outlet from the blower 112 hasa by-pass 152 controlled by a suitable spring pressed relief valve 153.The setting of this valve is such that the discharge air pressure ismaintained at approximately 25 pounds pressure gauge.

This pressure supply is connected to a regulating device generallydesignated as 2R, and also to the fuel noz zles and fuel source. As willbe noted, a line 154 supplies the fuel bowl 122 with air under full pumppressure. Likewise, a line 168 from blower 112 is connected by branches169, 170, with each of the nozzles 136, 137, etc. Fig. 4'illustrates themanner of connection of the pressure line 169 with one of the fuelnozzles 136.

The regulator 2R has a diaphragm operated inlet valve 155 operated toand from a suitable seat by the air pressure acting downstream of thevalve 155 against a diaphragm 157 in a chamber 156. The diaphragm 157is, in turn, connected to a second diaphragm 162 by a reverse linkage159, 161), and 161. Each diaphrgam, in turn, is backed up by acompression spring such as 158 and 164.

The diaphragm 162 is exposed to fluid pressure from an hydraulic circuitcommunicated thereto by the line 163, which, in turn, is a regulatedfluid pressure varying in a controlled manner in response to throttleposition and engine speed. This pressure acting on the diaphragm 162 isopposed by the force of spring 164 acting in a balancing direction.Diaphragm chamber 156, of course, is exposed to the pressure downstreamof the valve 155, which pressure is, in turn, opposed by the spring 158.

An air line 165 is connected with the chamber 156 of the regulator 2Rand with each of the nozzles 136, 137, etc., through suitable branches166, 167, etc. The mannor of connection to the nozzle is specificallyillustrated in Fig. 4, and the operation and function of each will belater described.

As will be realized by those skilled in the art, in order to control theamount of fuel delivered through each nozzle, it is necessary toprecisely control the pressure drop across the metering restrictions146, etc., in each nozzle. To do this, it is necessary to control thedifference in pressure between the fuel pressure in the bowl 122(upstream of the fuel metering orifice) and line 166 (downstream of thefuel metering orifice). This is accomplished by variations in aregulating or reference pressure which is generated and supplied to theline 163 from the hydraulic circuit about to be described acting on theregulator 2R. This hydraulic circuit includes the fluid pump 113 drivenfrom line shaft 111 and connected to the reservoir 1% by a supply line181. A fluid discharge line 182 connects with the pump 113 and with avariable metering restriction device 183 which has a return line 152 tothe reservoir 1%. This variable metering device 133 contains an orificecontrolled by a tapered needle 184 biased to an open portion by spring185 acting beneath the head 1 86. The motor vehicle or engine of themotor vehicle mounts the usual accelerator pedal 187 connected by a rod188 with a pivoted cam 189. Within the air intake stack to the manifoldis a throttle valve 190 positioned by a lever arm connected by a rod 191with the same cam 189. The face of the cam 189 ride: on the head of themetering stem or rod 184, varying the open position of the metering rodwith throttle movement.

The mechanism so far described in Fig. 3 differs from that in Figs. 1and 2 only in the addition of the extra air pressure line 168, itsbranches 169 and 176, and the type of fuel nozzle used; otherwise, thesystem is the same and operates in the same manner. The nozzleconstruction is best illustrated in Fig. 4.

According to this figure, nozzle 136 has a barrel containing a cylinder194 which reciprocably mounts a piston 195 for operating a dischargevalve 196. A spring 197 resists valve opening. Within the head of thevalve is a passage 198 which extends upwardly into the stem tocommunicate with inlet ports 199 which are located a substantialdistance above the nozzle outlet.

Operation As stated above, the operation of the system in Fig. 3 issimilar to that in Figs. 1 and 2 above explained except for thedifference in nozzle construction. In this modification, the upper sideof the piston 195 is exposed to constant blower output pressure throughthe lines 163, 169, 179, etc. The lower side of the piston 195 isexposed to the pressure in lines 165, 166, 167, etc., from the regulator2R. The spring 197 is suitably calibrated to resist small differences inpressure above and below the piston 195 and retain the valve 196 seated.Accordingly, when valve 196 is seated, all of the fuel entering at 146will accumulate in a small puddle up to the inlet ports 199. When itreaches this level, it will be swept outwardly through the small passage198 by the continuous passage of air supplied by the pressure regulator2R through the lines 165, 166, 167, etc. The ports and passages 198 and199 are so dimensioned that, at about 15 pounds air pressure, the flowthrough the passages 198 will be at critical speed, so that changes inpressures downstream or within the manifold have no effect upon theamount of air flowing through the nozzles, and therefore no effect uponthe pressure within the nozzle beneath piston 195.

As in the previous modifications described, a check valve may be placedin the line 154 to maintain the fuel bowl 122 under pressure after theengine stops operating.

When the engine is stopped, valve 196 will remain closed in eachinjector nozzle, due to the fact that the pressure in the lines 165 and168 will decrease simultaneously. Although the pressure in the fuel bowl122 is retained, the flow of fuel to the nozzles is cut off by thesolenoid valve 107.

To start the engine, the ignition switch 106 is turned on, supplyingfuel under pressure to each of the nozzles. As the engine is cranked,this fuel under pressure will be forced out through the ports 199 in thepassages 198, in the form of a spray, by the air pressure delivered formthe pump 112.

After the engine starts, full blower pressure from the air pump 112 willbe available to operate the system, and substantially the same pressurewill exist above and below each of the pistons 195 in each of theinjector nozzles. Spring 1.97 holds each of the valves seated, so thatthe air through the lines 166, 167, etc., forces the fuel out throughthis restricted passage 193 in the valve of each of the nozzles.

The hydraulic circuit, including the pump 113 and its effects upon thepressure regulator 2R, is the same as that described in the operation ofFig. l, and a description of it will not be repeated here.

When the throttle 18*? is opened, which indirectly causes anincrease inthe pressure differential on the fuel upstream and downstream of themetering orifices 146, the same differential will operate on theopposite sides of the piston 195, producing a force, eventually, whichis great enough to compress the spring 197 and unseat each of the valves196 in each of the nozzles. With the valves 1% unseated, the flowcapacity of each nozzle is increased a like amount, depending, ofcourse, upon the amount of displacement of the piston against the springin each nozzle. As each of the valves 196 opens, or as each is forcedfrom its seat, the amount of fuel which has accumulated between thevalve seat and the orifices or ports 199 will be discharged so as toenrich the fuel mixture delivered to the engine, and thus smooth out theacceleration in engine speed.

By the use of the nozzle shown in Fig. 4, several distinct advantagesare gained. A like amount of fuel will accumulate in each nozzle foruniform charging of each engine intake port. This can be determined bythe distance of the inlet port 199 above the outlet of the nozzle. Thesecan be made uniform in each nozzle for uniform metering. In the priorconstruction, the minimum size of the nozzle outlets 76, 77, etc., wouldbe determined by the maximum amount of fuel supplied to the engine. Thissize would require a large air pump to supply enough air to the nozzleand still maintain the required pressure in the chamber to control thefuel flow. By using the valve which opens as the fuel flow increases,the amount of air used at low pump speeds and engine speeds is therebydrastically reduced.

In the modification shown in Figs. 5 and 6, a system similar to thosepreviously described is shown in which the principal difference residesin two features. According to this modification, the pressure dropacross each of the fuel metering orifices in the respective nozzles iscontrolled in response to the rate of air flow to the engine measuredirectly by a flow responsive valve. The second difference resides inthe particular fuel nozzles in which the fuel metering orifices arelocated. In this modification, the rate of air flow to the engine notonly controls the pressure drop across the fuel metering orifices in allthe nozzles, but also the size or area of these orifices simultaneouslyproducing a like variation in the outlet for each of the nozzles.

As in the previous views, the engine is not shown, since it forms nopart of the invention, and the air induction system which is merelyschematically illustrated, is one adapted to serve a multiple ofcylinders having suitable inlet ports. Elements in Figs. 5 and 6corresponding with those previously described will be indicated by thesame reference characters preceded by 200.

The air induction system has an air intake stack 201 connecting with amanifold 202 having a plurality of outlets 2113 and 294, two of whichare shown. In the intake stack 201 are two pivoted valves 208 and 290,the latter of which is a manually controlled throttle valve.

In order to retain the fuel end of the system under pressure at alltimes, even when the engine is inoperative, and at the same time shutoff the fuel from the engine, this system is provided with a similarcontrol to those previously described, operated from the ignition switch206 which connects the battery B with a solenoid operated valve 207 whenthe ignition is on. When the ignition is off, the solenoid valve 207 isde-energized so that the valve can close, shutting off the fuel from theengine.

The fuel part of the system includes a pulley 209 suitably driven atengine speed on a line shaft 210 which, in turn, drives the fuel pump211 and the air blower 213. Fuel is supplied to the pump 211 from asuitable source 215, and is delivered by that pump to a line 216. Aroundthe pump 211 is a by-pass 217 containing a pressure limiting valve 219.This by-pass insures a constant supply of fuel under pressure throughthe line 216 to a. float bowl 222. The admission of fuel to the floatbowl 222 is under control of fioat valve 223 operated from the float 11224. Fuel is discharged through a line 225 past the solenoid operatedvalve 207 to a plurality of fuel nozzles 236, 237, etc., by way ofbranch lines 226 and 227.

The fuel enters each of the nozzles 236, etc., through a line 226 asillustrated in Fig. 6, and flows out of the nozzle through a meteringrestriction 246 into a chamber where it mixes with air supplied to thenozzle through the line 266. Fuel mixed with air is discharged throughthe metered outlet nozzle 276 adjacent the outlets 203, 204, etc., ofthe intake manifold and into the engine. The modification in Fig. 6differs from prior nozzles shown in the other modifications in that thefuel metering orifice 246 and the nozzle area 276 are simultaneouslyvariable in response to variations in air pressure differentials, aswill be described hereinafter. Within the body of the nozzle 236 is adouble-tapered metering rod 239 actuated by a diaphragm 240 and spring241. Air pressure from the line 266 is supplied to one side of thediaphragm 240, while fuel pressure from the line 226 is supplied to theopposite side of the diaphragm 240. As in prior devices, the pressuredrop across the metering orifice 246 is controlled by the air pressuredrop through the pressure regulator 3R connected with each line 266,267, by the supply line 265.

The air pressure to the nozzles is supplied by a separate circuitincluding the blower 213 driven by the engine through the pulley 209taking air in through an inlet 250, which may be connected with theinlet stack 201 posterior of the throttle 290, if desired. The dischargepressure from the blower 213 is regulated by the pressure relief valve253 in the by-pass line 252, and the air is discharged through the line251 to the pressure regulator 3R.

In the pressure regulator is a valve 255 controlled by a diaphragm 257and a balance spring 258 calibrated to give a maximum output pressureonly slightly lower than the output pressure from the blower 213. Airpassing the valve 255 enters a chamber 256 where it acts in a closingdirection against the opposition of the calibrated spring 258. Thepressure in the chamber 256 is communicated to the supply line and thenozzles by the branch lines 266, 267, etc., from line 265.

In this modification, the regulating pressure is supplied through aby-pass around the fuel pump controlled by an air flow responsive devicein the inlet stack of the manifold. This system includes a line 282containing a fixed metering orifice 291 communicating fuel pump outputpressure to the opposite side of the diaphragm 257. An orifice 283controlled by the tapered needle 284- throtties the discharge of fuelfrom this side of the diaphragm 257 to a by-pass relief line 292 leadingto the inlet of the fuel pump 21].. The position of the tapered needle28d, and therefore the exposed area of the orifice 283 is controlleddirectly by the rate of air flow through the inlet stack 201 by anunbalanced valve 2% having a counterweight. A link 298 connects needle284 with arm 289 on the shaft of the unbalanced valve 208. As theregulating fuel pressure increases, it tends to open the valve 255,aiding the action of the spring 258. On the other hand, as the datumfuel pressure decreases, the force tending to open the valve 255decreases.

The air pressure supplied by the blower 213 is impressed upon the fuelin the fuel bowl 222 by way of a line 254, so that the pressuredifferential across the fuel metering orifice 246 in the nozzles 236,237, etc, depends upon the degree of throttling of the valve 255, whoseposition, in turn, is influenced by the fuel pressure in the hydrauliccircuit 262, 283, and 292, from the pump 211i, and the pressure of theair acting on the upper side of the diaphragm 257.

Output pressure from the pump 211 is limited by the relief valve 219 inby-pass passage 217 to a maximum slightly greater than the maximumoutput pressure from blower 213 as limited by relief valve 253 inby-pass line 252. Accordingly, the pressure available in the hydrauliccircuit to regulator SR is always sufiicient to overcome the airpressure acting on the opposite side of the diaphragm tending to closevalve 255. In order to regulate the degree of opening of valve 255, line282 directly from pump 211 has a metering orifice 291, so

that, when the open areas of restricting device 283 and 291 are equal,pressure beneath diaphragm 257 remains constant. When the open area of233 is larger than the open area of 291, the pressure will fall beneathdiaphragm 257. When the open area of 283 is less than 291, the pressurebeneath diaphragm 257 increases.

Operation When the engine is not operating, the parts are in theposition as shown in Figs. 5 and 6. To start the engine, the ignitionswitch 206 is turned on, thereby supplying fuel under pressure throughthe connection 225 to the separate fuel nozzles 236, 237, etc. Duringcran..- ing of the engine, surplus fuel flow into the nozzles, due tothe pressure differential between the fuel bowl and the nozzles, willaccumulate above the orifice 276, valve 255 will open wide, and airunder pressure will be supplied from the blower 213 to each of thenozzles through the line 265. The accumulation of gasoline in thenozzles will supply a rich mixturein other words, little air and a greatdeal of fuel-so as to make starting easy.

After the engine begins to run, both fuel pressure output and airpressure output come up to operating limits, say 30 and 25 pounds,respectively. With valve 288 slightly open to accommodate low air flowrates suitable at engine idling speeds, restricting device 283 will havea minimum open area, causing the pressure in the hydraulic circuit tobuild up to maximum, opening valve 255' so that it produces only aslight throttling efiect on air flow to the nozzles, sufficient to givea slight pressure drop across the fuel metering orifices 246 for lowfuel flow. In this phase of the operation, the air pressure ondiaphragms 240 will be almost equal to the fuel pressure acting on thediaphragms 240 in each of the nozzles, and springs 241 will move thedouble tapered needles to their lower position within the orifices 246and 2'76 to reduce their open area to minimum. When the amount ofopening in the orifices 276 is minimum, a pressure drop of 15 poundsproduces a fiow at critical speeds. This maintains an air pressuredownstream of the fuel metering orifices 246 to the regulated pressure.The fuel pressure upstream of the orifices 246 will be the same asblower discharge pressure, or 25 pounds.

As the throttle 290 is opened manually, valve 208 will respond accordingto the rate of air flow through the intake stack 201. Needle 284 willthen take up a new position, opening orifice 283 to lower the fuelpressure below the diaphragm 257. Regulator SR is unbalanced by loweringthe pressure below diaphragm 25? in a direction tending to close valve255. As the valve moves toward closed, its throttling action lowers theair pres sure on the upper side of diaphragm 257 until air pressurebalances spring pressure and the decreased fuel pressure. Since thepressure in chamber 256 of the regulator 3R drops with throttle opening,while the fuel pressure from the source 222 remains constant, diaphragms240 in each of the nozzles overcomes the force of springs 241 to take upa new position, enlarging the metering orifices 246 for fuel toaccommodate increasing fuel flow. Simul taneously, orifice 276 isenlarged to facilitate the delivery of larger quantities of fuel. Itwill be understood that each change in throttle setting and each changein engine speed will produce a different setting for the air valve 208,and thereby a change in the air pressure in regulator 3R supplying thefuel nozzles 236, 237, etc. Each change in air pressure in turn variesthe fuel delivery from the nozzles by changing the pressure drop acrossthe metering orifices 246 and their area in each nozzle. The areaadjustment may be effected through either a part of the range ofpressure variations or through out the full range.

When the ignition switch 206 is turned off, the fuel flow to the nozzlesis stopped by the closing of the sole noid valve 207.

Fig. 7 shows a modification in which the regulating pressure supplied tothe regulator R is controlled by engine speed, throttle position, andmanifold pressure. When all three are combined as illustrated, theregulating pressure includes a compensation for change in altitude ordensity.

As in the previous views described, this system is schematicallyillustrated, and the engine is not shown, since it forms no part of theinvention. The elements shown in Fig. 7 which correspond with thosepreviously described in Figs. 1 and 2 will be indicated by the samereference characters preceded by 300.

This description will be limited to the differences over thosepreviously described in Figs. 1 and 2.

In this embodiment, the variable regulating or reference pressure isgenerated by a pump 313 driven at engine speed and supplied by a line363 from an hydraulic circuit about to be described.

The output of pump 313 connects by way of a line 332 and 332' with twometering devices 383 and 383. Within these metering devices are variablemetering rods 384 and 384 which control the flow of fuel through eachmetering device into a return line 392 and 392 leading back to a sump380. The hydraulic fluid in the sump 336 feeds to the pump 313 throughan input line 3831.

Within the metering device 383 is an orifice controlled by a movabletapered needle 384 positioned by a spring 385 acting under a fixed head386 on the needle 384. The position of the needle 384 in the orifice iscontrolled through a cam 389 connected by a link 388 with theaccelerator pedal 387 of the motor vehicle. A link 391 connects with thethrottle valve 390 within the intake stack 301 which supplies the air tothe intake manifold of the engine.

Within the metering device 383' is an orifice controlled by a taperedneedle 384', in turn positioned by a spring 385 acting beneath the head386' of the needle. A cam 389' engages the head 386' and limits theoutward movement of the needle from the orifice. The cam is, in turn,positioned by a link 398 connected with the diaphragm 396 of the suctionmotor394. A pipe 395 connects the suction motor 394 to the intake stackof the manifold 301 posterior of the throttle 390. Suction beneath thethrottle valve 390 acts on the diaphragm 396 in a direction to compressthe spring 397, and the diaphragm is moved to the left by the pressuredifferential existing between atmosphere and the pressure posterior tothe throttle 390, which will be greatest when throttle 390 is in closedposition. Spring 397 is suitably calibrated to move the link 398 to theright as the 'pressure differential on the diaphragm 396 decreases.

The regulating pressure in the line 363 will therefore be a function ofengine speed, throttle opening, and manifold pressure, so that, withthis system, decreases in atmospheric pressure operate on the mixturecontrol.

In all other respects, this system is identical with that shown in Fig.1, and a further description of the construction and operation is deemedunnecessary in view of the preceding description.

A structure has been described which will fulfill all the objects ofthis invention, but it is contemplated that other modifications willoccur to those skilled in the art which come Within the scope of theappended claims.

We claim:

1. A fuel injection system for an internal combustion engine having anair passage for supplying air to the engine comprising, in combination,a source of fuel, a fuel passage connecting said source and said engine,a fuel metering restriction in said passage, pump means for supplying afluid under positive pressure to said source, separate passagesconnecting said pump means with said fuel passage at spaced locationsupstream and downstream of said fuel metering restriction, means actingto control the fluid pressure in said separate passages to control thepressure differential across said fuel metering restriction and therebythe rate of fuel flow to said engine, means responsive to changes in therate of air flow to said engine for regulating the action of saidcontrol means, and means for injecting the fuel passing said fuelmetering restriction into said engine.

2. A fuel injection system for an internal combustion engine having anair passage for supplying air to the engine comprising, in combination,a source of air under pressure, a source of fuel, a fuel passageconnecting said source of fuel and said engine, a fuel meteringrestriction in said passage, air passages connecting said source of airunder pressure with said fuel passage at spaced locations upstream anddownstream of said fuel metering restriction, respectively, means actingto control the air pressure in said air passages to control the pres:sure differential across said fuel metering restriction and thereby therate of fuel flow to the engine, means responsive to changes in throttleposition and engine speed for regulating the action of said controlmeans, and means for injecting the fuel passing said fuel meteringrestriction into said engine.

3. A fuel injection system for an internal combustion engine having anair passage for supplying air to the engine comprising, in combination,a source of fuel, a fuel passage connecting said source and said engine,a fuel metering restriction in said passage, an air pump, separate airpassages connecting said air pump with said fuel passage at spacedlocations respectively upstream and downstream of said fuel meteringrestriction, means acting to control the air pressure in said separatepassages to control the pressure differential across said fuel meteringrestriction and thereby the rate of fuel flow to said engine, meansresponsive to air pressure in said engine induction air passage andengine speed for regulating the action of said control means, and meansfor injecting the fuel passing said fuel metering restriction into saidengine.

4. A fuel injection system for an internal combustion engine having anair passage for supplying air to the engine comprising, in combination,a source of fuel, a fuel passage connecting said source and said engine,a fuel metering restriction in said passage, a source of air underpositive pressure, separate air passages connecting said source of airunder pressure with said fuel passage at spaced locations respectivelyupstream and downstream of said fuel metering restriction, means actingto control the air pressure in said separate passages to control thepressure differential across said fuel metering restriction and therebythe rate of fuel flow to said engine, means responsive to changes inthrottle position and engine speed for regulating the action of saidcontrol means, and a fuel nozzle having an outlet in said air passagefor supplying air to the engine, forming a part of said fuel passagebetween said source and said engine and a part of one of said separateair passages between said source of air under pressure and said fuelpassage downstream of said fuel metering restriction.

5 A fuel injection system for an internal combustion eng ne having anair passage for supplying air to the engine comprising, in combination,a source of fuel, a fuel passage connecting said source and the engine,a fuel metering restriction in said passage, a source of air underpressure, separate air passages connecting said source of air underpressure with said fuel. passage at spaced locations respectivelyupstream and downstream of said fuel metering restriction, means tocontrol the air pressure in said separate passages to control thepressure differential across said fuel metering restriction and therebythe rate of fuel flow to said engine, means responsive to changes inthrottle position and engine speed for regulating said controlmeans, andmeans for injecting the fuel into said engine, including a fuel nozzlehaving an outlet of variable area opening into said air passage forsupplying air to the engine and forming a portion of said fuel passagebetween said source of fuel and said engine and a part of one of saidseparate air passages connecting said source of air under pressure withsaid fuel passage downstream of said fuel metering restriction, a valvefor varying the outlet from said nozzle having a metered openingconstantly in communication with said engine, and means for varying thearea of said outlet by valve movement including means for operating saidvalve in an opening direction in response to the differential inpressure between said separate air passages.

6. A fuel injection system for an internal combustion engine having anair passage for supplying air to the engine comprising, in combination,a source of fuel supply for the engine, a fuel passage between saidsource and the engine, a fuel metering restriction in said passage, asource of air under pressure, separate air passages connecting saidsource of air under pressure with said fuel passage at separatelocations respectively upstream and downstream of said fuel meteringrestriction, means to control the air pressure in said separate passagesto control the pressure differential across said fuel meteringrestriction and thereby the rate of fuel flow to said engine, meansresponsive to changes in throttle position and engine speed forregulating the action of said control means, and means for injecting thefuel metered into said engine, including a fuel nozzle opening into saidair passage for supplying air to the engine and forming a part of one ofsaid separate air passages connecting said source of air under pressurewith said fuel passage downstream of said fuel metering restriction anda part of said fuel passage including said fuel metering restriction,means responsive to fuel pressure upstream of said fuel meteringrestriction and said air pressure downstream of said fuel meteringrestriction for varying the area of said fuel metering restriction andthe outlet from said nozzle.

7. A fuel injection system for an internal combustion engine having anair passage for supplying air to the engine, comprising, in combination,a source of fuel supply for the engine, a fuel passage between saidsource and said engine, a fuel metering restriction in said fuelpassage, a source of air under pressure, separate air passagesconnecting said source of air under pressure with said fuel passage atseparate locations upstream and downstream, respectively, of said fuelmetering restriction, means to control the air pressure in said separatepassages to control the pressure differential across said fuel meteringrestriction and thereby the rate of fuel flow to said engine including avalve in one of said separate air passages connecting said source of airunder pressure with said fuel passage downstream of said fuel meteringrestriction, means responsive to air pressure downstream of said valvefor urging said valve toward a closed position, a hydraulic circuithaving an output pressure variable in response to changes in throttleposition and engine speed, and means responsive to changes in hydraulicpressure in said hydraulic circuit for urging said valve toward a closedposition.

8. The combination of an engine, an air induction system for saidengine, and a fuel injection system for supplying fuel to a plurality ofnozzles located in said induction system adjacent the air intake portsof the engine, comprising, a source of fuel for supplying said engine,branched fuel passage means connecting said source and each of saidnozzles, a fuel metering restriction in each of the branches of saidpassage means to said nozzles, an air pump for supplying air underpositive pressure, separate passages connecting said air pump with saidfuel passage means at spaced points located respectively upstream anddownstream of each of said fuel metering restrictions, means to controlthe fluid pressure insaid separate air passages to uniformly control thepressure differential across each of said fuel metering restrictions andthereby the total rate of fuel flow to said engine from said source offuel and maintain equal rates of flow past each of said fuel meteringrestrictions, means responsive to changes in the rate of air flow tosaid engine through said induction system for regulating the action ofsaid control means, and means in said nozzles for injecting the fuelpassing said fuel metering restrictions into said engine.

9. In combination, an engine, an air induction system for said engine,and a fuel injection system for supplying fuel to a plurality of nozzleslocated in said air induction system adjacent the air intake ports ofsaid engine, comprising a source of fuel supply for said engine, a fuelpassage between said source and each of said nozzles, a fuel meteringrestriction in each of said fuel passages, an air pump, separate airpassages connecting said air pump with said fuel passages at spacedlocations respectively upstream and downstream of each of said fuelmetering restrictions, means to uniformly control the air pressure insaid separate air passages to control the pressure differential acrosseach of said fuel metering restrictions and thereby the total rate offuel flow to said engine from said source of fuel and maintain equalrates of flow past each of said fuel metering restrictions, meansresponsive to changes in throttle position and engine speed forregulating the action of said control means, and means in said nozzlesfor injecting the fuel passing said fuel metering restrictions into saidengine.

10. In combination, an engine, an air induction system for said engine,and a fuel injection system for supplying fuel to a plurality of nozzleslocated in said air induction system adjacent the air intake ports ofthe engine, comprising a source of fuel supply for the engine, a fuelpassage between said source and each of said fuel nozzles, a fuelmetering restriction in each of said fuel passages, an air pump drivenfrom said engine, pairs of separate air passages each connecting saidair pump respectively with one of said fuel passages upstream of thefuel metering restriction therein and the corresponding fuel nozzledownstream of said fuel metering restriction, means to uniformly controlthe air pressure in said separate passages to control the pressuredifferential across said fuel metering restrictions and thereby thetotal rate of fuel flow to said engine from said source of fuel andmaintain equal rates of flow past each of said fuel meteringrestrictions, means responsive to air pressure in said engine inductionair passage and engine speed for regulating the action of said controlmeans, and means connected with said nozzles for injecting the fuelpassing said fuel metering restrictions into said engine.

11. In combination, an engine, an air induction system for said engine,and a fuel injection system for supplying fuel to a plurality of nozzleslocated in said induction system adjacent the air intake ports of theengine, comprising a source of fuel supply for said engine, a fuelpassage between said source of fuel supply and said engine and each ofsaid nozzles, a fuel metering restriction in each of said fuel passages,a source of air under positive pressure, pairs of air passages eachconnecting said source of air under pressure with one of said fuelpassages at spaced locations respectively upstream and downstream of thefuel metering restriction therein, means to uni formly control the airpressure in the groups of separate air passages at points connectingwith said fuel passages respectively upstream and downstream of saidfuel metering restrictions to control the pressure differential acrosseach of said fuel metering restrictions and thereby the total rate offuel flow to said engine from said source of fuel and maintain equalrates of flow past each of said fuel metering restrictions, meansresponsive to changes in throttle position and engine speed forregulating the action of said control means, and an outlet for each ofsaid nozzles opening into said air induction manifold for said engineselected to produce air flow at critical speeds from the nozzle toeliminate the effects of pressure varia- I? tion in said air inductionsystem on the fuel metering function.

12. In combination, an engine, an air induction system for said engine,and a fuel injection system for supplying fuel to a plurality of nozzleslocated in said induction system adjacent the air intake ports of saidengine, comprising a source of fuel supply for the engine, a fuelpassage between said source of fuel supply and said fuel nozzles, a fuelmetering restriction in said fuel passage upstream of each of saidnozzles, a source of air under pressure, separate air passagesconnecting said source of air under pressure with said fuel passage atseparate locations upstream and downstream, respectively, of each ofsaid fuel metering restrictions, means to uniformly control the airpressure in said separate air passages leading upstream and downstreamof said fuel restrictions to control the pressure differential acrosssaid fuel metering restrictions, and thereby the total rate of fuel flowto said engine from said source of fuel and maintain equal rates of fuelflow past each of said fuel metering restrictions, means responsive tochanges in throttle position and engine speed for regulating saidcontrol means, outlet means in said fuel nozzles opening into said airinduction system for said engine and forming a portion of said fuelpassage between said source of fuel and said engine and also forming aportion of said separate air passages connecting said source of airunder pressure with said fuel passage downstream of each of said fuelmetering restrictions, a valve for varying said outlet means from eachof said fuel nozzles having metered openings constantly in communicationwith said engine, and means for varying the area of said outlet means byvalve movement including means for operating said valves in an opening,direction in response to the differential in pressure between saidseparate air passages.

13. In combination, an engine, an air induction system for said engineand a fuel injection system for supplying fuel to a plurality ofnozzles'located in said air induction system adjacent the air intakeports of the engine, comprising a source of fuel supply for the engine,a fuel passage between said source of fuel supply and each of saidnozzles, a plurality of fuel metering restrictions in said passage, eachbetween said source of fuel supply and one of said nozzles, a source ofair under pressure, separate air passages connecting said source of airunder pressure with said fuel passage at separate locations respectivelyupstream and downstream of each of said fuel metering restrictions,means to uniformly control the air pressure in said separate passagesleading downstream of saidvfuel metering restrictions to control thepressure differential across each of said fuel metering restrictions andthereby the total rate of fuel flow to said engine from said source offuel supply and maintain equal rates of fiow past each of said fuelmetering restrictions, means responsive to changes in throttle positionand engine speed for regulating the action of said control means, meansforming an outlet in each of said fuel nozzles for receiving air fromsaid separate air passages connecting with said source of air underpressure and fuel from said fuel metering restrictions, and means ineach of said nozzles responsive to fuel pressure upstream of said fuelmetering restrictions and air pressure downstream of each of said fuelmetering restrictions for varying the area of said fuel meteringrestrictions and the outlet from each of said nozzles.

14. In combination, an engine, an air induction system for said engineand a fuel injection system for supplying fuel to a plurality of nozzleslocated in said induction system adjacent the air intake ports of saidengine comprising a source of fuel supply for said engine, a fuelpassage between said source of fuel supply and each of said nozzles, afuel metering restriction in said fuel passage between said source offuel supply and each of said nozzles, a source of air under pressure,separate air passages connecting said source of air under pressure withsaid fuel passage at separate locations respectively upstream anddownstream of each of said fuel metering restrictions, means touniformly control the air pressure in said separate air passages tocontrol the pressure differential across each of said fuel meteringrestrictions and thereby the total rate of fuel flow to said engine fromsaid source of fuel and maintain equal rates of flow past each of saidfuel metering restrictions including a valve in each of said separateair passages downstream of each of said fuel metering restrictions,means responsive to air pressure downstream of each of said valves forurging said valves toward a closed position, an hydraulic circuit havingan output pressure variable in response to changes in throttle positionand engine speed, and means responsive to changes in hydraulic pressurein said hydraulic circuit for operating said valves.

15. A system for maintaining a proportional flow of air and fuelsuitable for combustion comprising an air flow passage with means forvarying the air flow through said passage, a hydraulic circuit, means insaid. circuit for generating an output pressure, means in said circuitmovable with changes in air fiow through said air passage for varyingthe output pressure in said circuit, a fuel passage including a supplyof fuel and a fuel outlet opening into saidair flow passage, and apneumatic circuit including a source of air under pressure, an airpressure regulator controlled by the output pressure of said hydrauliccircuit, and passages connecting said pneumatic circuit upstream anddownstream of said regulator With said fuel passage for varying the fuelpressure head on the fuel in said fuel passage.

p 16. A system for maintaining a proportional flow 0 air and fuelsuitable for combustion comprising an air flow passage with means forvarying the air flow through said passage including a valve, a hydrauliccircuit, means in said circuit for generating an output pressure, meansin said circuit connected with said valve for varying the outputpressure in said hydraulic circuit, a fuel passage including a supply offuel and a fuel outlet opening into said air flow passage, and apneumatic circuit including a source of air under pressure, an airpressure regulator controlled by the output pressure of said hydrauliccircuit, and passages connecting said pneumatic circuit upstream anddownstream of said regulator with said fuel passage for varying the fuelpressure head on the fuel in said fuel passage.

17. A system for maintaining a proportional fiow of air and fuelsuitable for combustion comprising an air passage with means for varyingthe air flow through said passage including a valve, pressure indicatingmeans connected with said air passage, a hydraulic circuit, means insaid circuit for generating an output pressure, means in said circuitconnected with said pressure indicating means for varying the outputpressure in said hydraulic circuit, a fuel passage, a supply of fuelconnected with said fuel passage, 21 fuel outlet for said fuel passageopening into said air passage, a pneumatic circuit including a source ofair under pressure, an air pressure regulator controlled by the outputpressure of said hydraulic circuit, and passages connecting saidpneumatic circuit upstream and downstream of said air pressure regulatorwith said fuel passage for varying the fuel pressure head on the fuel insaid fuelpassage.

18. In combination, an engine, an air induction system for said enginehaving a throttle, and a fuel injection system for supplying fuel to aplurality of nozzles located in said air induction system, comprising asource of fuel under pressure, fuel passages between said source of fuelunder pressure and each of said fuel nozzles, a fuel meteringrestriction having the same fuel flow characteristics in each of saidfuel passages, a source of air under positive pump pressure, airpassages connecting said source of air under pressure with said nozzlesdownstream of said fuel metering restriction, means to uniformly controlthe air pressure in said air passages to control the pressuredifferential across said fuel metering restrictions and thereby thetotal rate of fuel flow to said engine from said source of fuel underpressure and maintain equal rates of flow past each of said fuelmetering restrictions, and means responsive to throttle opening andengine speed for regulating the action of said control means.

19. In a fuel metering device for an internal combustion engine having athrottle controlled air intake with branches extending to the enginecombustion chambers, the combination of a system for maintaining theflow of fuel to the engine combustion chambers proportional to the flowof air to the engine comprising a source of fuel under a constantcharging pressure, a plurality of passages connecting said source withsaid engine combustion chambers, a fixed metering orifice in each ofsaid fuel passages all having substantially identical flowcharacteristics, a variable regulating pressure system including asource of air under pump pressure, means to vary the regulating pressurein said system in response to changes in the rate of air flow to theengine, and means for controlling the pressure downstream of each ofsaid metering orifices connected to said regulating pressure system.

20. In an engine charge forming device having a throttle-controlled airintake with branches leading to the combustion chambers of the engine,the combination of a source of fuel under charging pressure, a pluralityof fuel passages connecting said source with the combustion chambers ofthe engine, a variable area fuel metering orifice in each of said fuelpassages, a regulating pressure system, means for generating aregulating pressure in said system which varies in response to changesin the rate of air flow to the engine through said air intake, and amotor means to vary each of said variable fuel metering orificesoperated in response to the difference between said charging pressureand said regulating pressure.

- v21. In an engine charge forming device for an internal combustionengine having a throttle controlled air intake with branches extendingto the separate combustion chambers of the engine, the combination of asource of fuel under charging pressure, a fuel nozzle discharging intoeach of the combustion chambers of the engine, separate fuel passagesconnecting said source of fuel under pressure and each of said fuelnozzles, a variable metering restriction between the source of fuelunder pressure and each of said nozzles, a motor means for operatingeach of said variable metering restrictions, a source of air underpressure connected to each of said fuel passages downstream of themetering restriction therein, means for varying the air pressure fromsaid source in response to changes in the rate of air flow to theengine, and means for operating said motor means for varying the area ofeach fuel metering restriction in response to change in the differentialbetween fuel charg-' ing pressure and air pressure.

22. In a fuel metering device for an internal combustion engine having athrottle controlled air intake with branches extending to the combustionchambers of the engine, the combination of a fuel pump, a fuel bowlsupplied from said pump, a float valve for controlling the fuel level insaid bowl, a plurality of fuel nozzles located in said branches, fuelpassage means ations in the rate of air flow to the engine past saidthrottle for controlling the differential between air pressure in saidfuel bowl and in said air passage means.

23. In an engine charge forming device, the combination comprising anintake manifold having branches connected with the combustion chambersof the engine, a throttle valve in said manifold, a regulating fluidpressure system, means for controlling the pressure in said regulatingpressure system, means responsive to variations in engine speed andthrottle opening for operating said control means in said system, asource of fuel, a fuel pump supplied from said source, a plurality offuel nozzles located in said branches, branch fuel passages extendingbetween said pump and said nozzles, fuel metering devices forrestricting the rate of fuel flow through each of said branches, meansfor varying the fuel pressure downstream of said metering devices, and aconnection between said means for varying the fuel pressure and saidregulating system.

. .24. In an engine charge forming device, the combination comprising anintake manifold having branches connected with the combustion chambersof the engine, a throttle valve in said manifold, a regulating fluidpressure system, means for generating a pressure in said regulatingpressure system, means responsive to variations in engine speed andthrottle opening for controlling the pressure in said regulatingpressure system, a source of fuel, a fuel pump supplied from saidsource, open fuel nozzles in said branches, branch fuel passages betweensaid pump and said nozzles, a plurality of fuel metering, devices insaid fuel passages, means for varying the opening in said open fuelnozzles, and separate connections from said regulating system and saidfuel pump to operate said means to vary the fuel nozzle opening.

No references cited.

